After some time, the VAX crashed. It was on a service contract, and Digital was called. Laura Creighton was not called although she was on the short list of people who were supposed to be called in case of problem. The Digital Field Service engineer came in, removed the disk from the drive, figured it was then okay to remove the tape and make the drive writeable, and proceeded to put a scratch disk into the drive and run diagnostics which wrote to that drive.
Well, diagnostics for disk drives are designed to shake up the equipment. But monkey brains are not designed to handle the electrical signals they received. You can imagine the convulsions that resulted. Two of the monkeys were stunned, and three died. The Digital engineer needed to be calmed down; he was going to call the Humane Society. This became known as the Great Dead Monkey Project, and it leads of course to the aphorism I use as my motto: You should not conduct tests while valuable monkeys are connected, so "Always mount a scratch monkey."
Laura Creighton points out that although this is told as a gruesomely amusing story, three monkeys did lose their lives, and there are lessons to be learned in treatment of animals and risk management. Particularly, the sign on the disk drive should have explained why the drive should never have been enabled for write access.